Origin of directional tear in blown films of ethylene/methacrylic acid copolymers and lonomers

L. I.Bong W. Lee, Richard Alan Register, David M. Dean

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Blown films of ethylene/methacrylic acid copolymers and ionomers can exhibit pronounced directional tear, meaning that a tear can propagate with much less resistance in a particular direction. However, films blown from the same resin can exhibit different preferred tear directions, which depend on the process conditions. Through wide- and small-angle X-ray scattering, we demonstrate that this directional tear behavior is a direct result of the orientation of the lamellar polyethylene crystallites in these films; tears propagate more readily between lamellae than through lamellae, as previously recognized for low-density polyethylene homopolymer. Unlike polyethylene homopolymer, however, an increase in the blowup ratio during the film processing of ethylene/methacrylic acid copolymers and ionomers leads to a 90° rotation of the lamellae that form upon subsequent crystallization. The lamellar rotation arises from a change in the orientation of the row nuclei that form after the melt is inflated and produces a consequent rotation of the preferred tear direction.

Original languageEnglish (US)
Pages (from-to)97-106
Number of pages10
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume43
Issue number1
DOIs
StatePublished - Jan 1 2005

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Keywords

  • Films
  • Ionomers
  • Polyethylene (PE)
  • Tear
  • WAXS

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